Gamezilla recently posted a review of the PC version of Civilization IV: Warlords. The expansion introduces warlord units to the mix as well as new scenarios and nations. Gamezilla labeled Civ IV: Warlords a Recommended Buy.

From the review:

There are new units, including the trebuchet and the trireme, and new world wonders, including the Temple of Artemis, and the return of the Great Wall.

A new type of Great Person has been added, the Great General, who can appear after winning a battle. A Great General unit then can be moved around and converted into a warlord (thus the game's subtitle) by attaching it to a military unit. The stack in that square then immediately gets 20 experience points to spread promotions around. The attached unit also gets free upgrades for the rest of the game, a nice benefit. A Great General can also be spent to erect a military academy or become a super specialist that gives all units created in a city an experience bonus. And, last but not least, the warlord feature includes the possibility of attaching to naval units, so even though it's called a Great General it can be made into a seagoing warlord, to correct that glaring lack of admirals in the base game.